WTPA42 PHFO 112054
TCDCP2
HURRICANE FLOSSIE DISCUSSION NUMBER 13
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092007
1100 AM HST SAT AUG 11 2007
FLOSSIE CONTINUES TO BE AN IMPRESSIVE SYSTEM WITH GOOD UPPER LEVEL
OUTFLOW IN NORTH AND SOUTH QUADRANTS AND A SOLID EYEWALL AROUND A 17
NM EYE AS SEEN IN GOES IMAGERY. THE 1448 UTC SSM/I PASS ALSO
INDICATED A SINGLE CLOSED EYEWALL. OBJECTIVE DVORAK SHOWED 117 KT
AND SUBJECTIVE DVORAK INTENSITY ESTIMATES FROM PHFO AND SAB CAME UP
WITH 115 KT SO THE INITIAL INTENSITY WILL BE HELD AT 115 KT.
THE CURRENT MOVEMENT REMAINS TOWARD THE WEST AT 10 KT AS FLOSSIE
TRACKS SOUTH OF A SUBTROPICAL RIDGE. OBJECTIVE AIDS ARE GENERALLY
IN AGREEMENT FOR DAYS 1 AND 2 WITH A WEST-NORTHWEST TRACK.
HOWEVER...THE DIFFERENCES...AND THE UNCERTAINTY...INCREASE BEYOND
DAY 2. NOGAPS...HWRF...GFDL AND BAM-DEEP ARE ON THE RIGHT SIDE OF
THE GUIDANCE ENVELOPE WITH A MORE SIGNIFICANT TURN TO THE NORTHWEST
AND A PASSAGE EAST OF THE HAWAIIAN ISLANDS. THE GFS...ECMWF AND THE
JAPANESE SPECTRAL MODELS ARE ON THE LEFT SIDE OF THE ENVELOPE. THE
OUTCOME WILL DEPEND ON THE STRENGTH OF THE SUBTROPICAL RIDGE AFTER
DAY 2 AND THE EFFECTS OF INCREASING VERTICAL SHEAR AND COOLER SEA
SURFACE TEMPERATURES. IF THE SHEAR AND COOLER WATER TAKE A
SIGNIFICANT TOLL ON FLOSSIE...THE SOUTHERN TRACK WILL BE MORE
LIKELY. IF FLOSSIE CAN OVERCOME THESE FACTORS...THE TRACK WILL
FAVOR A CLOSER APPROACH TO THE HAWAIIAN ISLANDS. THE FORECAST
TRACK GENERALLY FOLLOWS THE PREVIOUS FORECAST...ROUGHLY DOWN THE
MIDDLE OF THE ENVELOPE...WITH A NORTHWARD NUDGE CLOSER TO THE BIG
ISLAND.
SEA SURFACE TEMPERATURES WILL DECREASE ALONG THE FORECAST TRACK WITH
FLOSSIE CROSSING THE 26.5C ISOTHERM OVER THE NEXT DAY OR SO. THE
VERTICAL SHEAR IS ALSO EXPECTED TO INCREASE AFTER DAY 2 ONCE
FLOSSIE CROSSES 150W. THESE FACTORS SHOULD CONTRIBUTE TO A STEADY
WEAKENING WITH THE INTENSITY FORECAST TO DROP BELOW HURRICANE
STRENGTH AFTER DAY 3.
IT IS IMPORTANT TO NOTE THAT ALTHOUGH THE CURRENT FORECAST KEEPS THE
CENTER OF FLOSSIE SOUTH OF THE HAWAIIAN ISLANDS...A CLOSER APPROACH
CANNOT BE RULED OUT.
FORECAST POSITIONS AND MAX WINDS
INITIAL 11/2100Z 13.0N 141.1W 115 KT
12HR VT 12/0600Z 13.4N 142.6W 115 KT
24HR VT 12/1800Z 13.9N 144.8W 105 KT
36HR VT 13/0600Z 14.5N 147.0W 95 KT
48HR VT 13/1800Z 15.2N 149.2W 85 KT
72HR VT 14/1800Z 16.7N 153.6W 65 KT
96HR VT 15/1800Z 18.1N 157.4W 50 KT
120HR VT 16/1800Z 19.5N 160.4W 40 KT
$$
FORECASTER KODAMA